Heavy-duty clutches are designed for vehicles engaged in motor sports or for vehicles that have to tow heavy loads. A heavy-duty clutch has increased resistance, which helps increase engine torque and provide more power from the engine to the transmission.
Cars that are racing, towing heavy loads or performing off-road motor sports rely on heavy-duty clutches to handle being bounced around and treated rougher than they would be while driving normally on a paved road. Heavy duty clutches have an increased clamp load on the clutch cover and may also feature either a cushion button or a heavy-duty button. A cushion button offers a better feel for a driver when changing gears, but a heavy-duty button offers a more secure lock in the clutch.